1. Field of the Invention
The present invention generally relates to a projector. More particularly, the present invention relates to a projector and the volume of the projector is minimized by a medium to adjust the refraction path of the light.
2. Description of Related Art
The advancement of multi-media systems in our society depends to a large extent on the progressive development of semiconductor devices and display devices. For displays, because direct-viewing displays have definite dimensional limitations, the integration of a high-resolution indirect viewing display panel with an efficient optical engine has become the mainstream design for producing a large rear projector and rear projection television.
FIGS. 1 and 2 are schematic cross-sectional views showing two kinds of conventional rear projectors. Please refer to FIG. 1, the conventional rear projector 100 transmits an optical image 112 to a display screen 120 through an imaging system 110. The optical image 112 of the rear projector 200 shown in FIG. 2 is provided by the imaging system 110. Because the imaging system 110 and the display screen 120 are disposed at the same side, the optical image 112 is transmitted to the display screen 120 by the reflection of the reflection mirror 130.
Please refer to FIGS. 1 and 2, the conventional rear projector utilizes the air as a transmission medium of the optical image 112. In other words, nothing is disposed between the imaging system 110 and the display screen 120 shown in FIG. 1, or between the reflection mirror 130 and the display screen 120 shown in FIG. 2. Because the refraction index of the air is a constant, the transmission path and the angle of the optical image 112 remain the same without any changes. However, if the included angle between the optical image 112 and the display screen 120 is wrong or the transmission path needs to be changed, the conventional rear projector can't adjust appropriately. Also, the volume of the rear projector is constrained by the design of the optical path, and the rear projector can't be thinner.